// My custom shader for implementing dithered alpha
shader_type canvas_item;

uniform sampler2D screen_texture : hint_screen_texture, repeat_disable, filter_nearest;

void fragment() {
    // Fancy dithered alpha stuff
    vec4 color = texture(screen_texture, SCREEN_UV);
    float opacity = color.r;
    int x = int(FRAGCOORD.x) % 4;
    int y = int(FRAGCOORD.y) % 4;
    int index = x + y * 4;
    float limit = 0.0;

    if (x < 8) {
        if (index == 0) limit = 0.0625;
        if (index == 1) limit = 0.5625;
        if (index == 2) limit = 0.1875;
        if (index == 3) limit = 0.6875;
        if (index == 4) limit = 0.8125;
        if (index == 5) limit = 0.3125;
        if (index == 6) limit = 0.9375;
        if (index == 7) limit = 0.4375;
        if (index == 8) limit = 0.25;
        if (index == 9) limit = 0.75;
        if (index == 10) limit = 0.125;
        if (index == 11) limit = 0.625;
        if (index == 12) limit = 1.0;
        if (index == 13) limit = 0.5;
        if (index == 14) limit = 0.875;
        if (index == 15) limit = 0.375;
    }
    // Is this pixel below the opacity limit? Skip drawing it
    COLOR = mix(vec4(0,0,0,0), vec4(1,1,1,color.a), step(limit, opacity));
}